In the present context, an automotive lighting system is understood to mean a system onboard a motor vehicle including an electrical circuit comprising electrical light sources and their electrical connections.
There are numerous electrical light sources on board of today's motor vehicles fulfilling defined lighting functions such as e. g. high beam, low beam, fog light etc. Additional to such lighting functions which have been used for many years, other functions such as a daytime running light (DRL) have recently been introduced. A light source fulfilling a DRL function should be turned on while the motor is running during the daytime, but should be turned off at night, i. e. if the low beam is activated.
While such functions may be easily realized in a newly manufactured automobile, retrofitting a vehicle with such a function requires an electrical connection of the light source used for the DRL lighting function not only with an electrical power supply, i. e. battery/electrical generator but also with a switch that ensures its correct function.
One possible way of retrofitting a vehicle with a light source with DRL lighting function is to connect it to the position light of the automobile. The position light is usually an electrical light source of very small electrical power that is activated together with the low beam lighting function. If the position light is on, the DRL light source must be turned off; if electrical power is present (i. e. the motor is running or at least the ignition is activated) and the position light is off, the DRL light source should be turned on. However, installing a DRL light source in this way requires an electrical connection to the position lamp wiring, and thus a modification to the original wiring of the automobile.
U.S. Pat. No. 5,909,084 describes a daytime running light adapter kit designed to be installed in a vehicle to allow the vehicle to be equipped with daytime running light. An electronic unit has a set of connectors to be connected to the vehicle light. The daytime running light adapter kit turns on the DRL lights only when the vehicle engine is operating and the manual front light switch is off.